Electric burglar-alarm



(No Model.)

' L. A. MGGARTHY.

ELECTRIC BURGL'AR ALARM.

No. 398,420. Patented Feb, 26, 18819,.

WHA/5885s.-

lauren@ .27.

ATTORNEY.

UNITED STATES PATENT EErcE.

LAURENCE A. MCOARTHY, OF BROOKLYN, NEIV YORK.

ELECTRIC BURGLAR-ALARIVL SPECIFICATION forming part of Letters Patent No. 398,420, dated February 26, 1889. Application filed April 18, 1888. Serial No. 271,040. (No model.)

To all whom t may concern.-

Be it known that I, LAURENCE A. MUGAR- THY, a citizen of the United States, residing in Brooklyn, in the county of Kings and State 0f New York, have invented certain new and useful Improvements in Electric Burglar- Alarms; and I do hereby declare that the following' is a full, clear, and exactdescription of the circuit shall be broken. The circuit passes thence to a spring, F, which is nor mally in contact with a corresilionding spring, G, as shown. From. G the circuit goes through D and D2 back to the generator.

my invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The object of my invention is to provide a simple and reliable burglar-alarm not likely to get out of order and requiring little attention. Alarms which are sent in by my system in consequence of any interruption or disturbance of the circuit are deiinite alarms which locate the pointot disturbance and enable a watchman to direct his attention to the proper locality.

My alarm devices are arranged to operate upon a normally-closed electric circuit. This admits of several alarm devices being connected up in the same circuit without interference. Besides my automatic alarm devices which are set off by the rupture of the circuit or short-circuiting, I may introduce into the circuit manual circuit-controllers, such as push-buttons or district-boxes.

I have illustrated my invention in the accompanying drawing, which represents a diagram of my system.

A is an electric generator, and B an electromagnetic gong. The latter may be located in the structure where my signaling devices are placed, or at a police-stati on or other point where watch is kept.

O O are manual circuit-eontrollers, which may be district-boxes capable of sending definite signals over the line.

The automatic devices,which constitute the main part of my burglar-alarm apparatus, are shown at D in detail, D and D2 being similar devices shown without detail.

The circuit passes, as shown, through the gong and the district-boxes through two magnets, E and E', acting in opposite directions upon armature a.. From the latter magnet it passes to a resistance, R, located at a door or Window to be protected. Such door or window will be provided with any suitable connections, so that on the opening of the same -leasing the signaling devices.

It will be observed that a branch. circuit after passing through magnet E traverses a resistance,R, and joins the circuit originally 6o described before reaching the spring F. The resistances R and R are substantially equal, and also the resistance of the magnet E is substantially equal to that oi' the magnet E.

The spring G is normally in contact with the periphery of a wheel, H, which tends to rotate in the direction of the arrow under the influence of clock-work. (Not shown.) Projecting from the wheel H is a detent-pin, c', which normally rests against an angular ex- 7o tension, j,of the armature u,or a pin traversing the said armature. The wheel is thereby prevented from rotating except when the ar mature is thrown toward one or the other of the magnets E E. In that case the obstructing stop j will be removed from the path of the detent-pin and the wheel will rotate.

Now the Wheel H is provided with a series of teeth representing a deiinite number. The wheel shown represents the number As 8o each tooth strikes spring G, the latter is moved away from F and breaks the circuit, sounding a definite signal on the gong.

The action of the apparatus is as follows: Suppose a burglar breaks the circuit at Rby opening the door or window. The circuit of magnet E will be broken, and the whole current will be thrown through magnet E, causing it to draw over the armature e, and thus releasing the signaling mechanism. It' 9o now the burglar immediately restores the door or window to its original condition, he will be too late to prevent the signal from being sent in at least once. It he fails to rcstore t-he circuit, the signal will be repeated until the clockwork operating the wheel H runs down. Similarly, if a short circuit is made at or near the window or door, cutting out the resistance R, the greater part of the current will then be thrown through E', re- Ico The action of the magnets E and E upon the armature a is manifestly equivalent to the action of a differential magnet. Any arrangement of magance R, might be run to a point to be protected, such as a door or window. may. be replaced by any other suitable receiving apparatus.

Having now described my invention, what I claim isl. In an electric signaling apparatus, the

main circuit divided into two parts or paths, the current normally ilowin g through both of them and always lowin g through one of them,

a magnetic coil and an artiiicial resistance in each part or path, the total resistance in each part or path being equal, an automatic detin'ite signaling apparatus, an armature normally balanced in a vertical position between the coils, and a clock-work Vfor operating said signaling apparatus, a revolving portion of said clock-work ha\f'ing upon its face a projection opposite to and abutting against the i end of the armature in its balanced position,

Th e gong said coils and to lock said apparatus when the energization of the d etlccting-magnetbecomes normal.

2. In an electric signaling apparatus, the main circuit divided into two parts or paths, the current normally flowing through both of them and always `[lowing through one of them, a magnetic coil and an artificial resistance in each part or path, the total resistance in each part or path being equal, an automatic detinite signaling apparatus, an armature normally balanced in a vertical position between the coils, and a clock-work for operating said and adapted to unlock said signaling apparatus by an excess of attraction of either of Y signaling apparatus, a revolving portion of said clock-work having upon its face a projection opposite to and abutting against the cnd of the armature in its balanced position, and adapted to unlock said signaling apparatus by an excess of attraction of either of said coils and to lock said apparatus when the energization of the deilecting-magnet becomes normal, all in combination with one or more of the same elements in the same eircuit and one or more manual ci rcnit-breakers, as set forth.

In witness whereof I have hereunto signed my name in the presence ot two subscribing witnesses.4

LAURENCE A. MCCARTHY.. Witnesses:

G. H. STOCKBRIDGE, FRANK C. GRUEY. 

